In A Christmas Carol, why does Scrooge care about the fate of Tiny Tim?

Part of Scrooge's redemption is to see his effect his treatment has on others, and see how he had been treated. His disregard to the destitute was summed up in the line "If they would rather die, they had better do it, and decrease the surplus population." When he travels with the Ghost of Christmas Present to the Cratchit's, Dickens has Scrooge say " Spirit,' said Scrooge, with an interest he never had before, ' tell me if Tiny Tim will live. ' " Scrooge is ashamed when he hears his statement repeated back. It's evident that after reviewing his own life as a child in Christmases past, and now witnessing Bob with his family, he's begun his transition and has begun to have some sympathy for Tiny Tim. After his redemption, Dickens states that Scrooge became "a second father" to Tiny Tim, because he's learned it was in his own best interest to help where he was able.